New mutations in the X-linked form of Charcot-Marie-Tooth disease.

Mutations in the gene for connexin 32 are associated with a chromosome X-linked form of Charcot-Marie-Tooth disease. The prevalence of this form is probably underestimated. We screened 12 candidate families and found 7 missense mutations of which 4 are new. These mutations are located in intra- and extramembraneous parts of the protein. Some mutations are probably present with a higher frequency. This study further confirms variation of connexin 32 mutations with scarcity in the second transmembrane domain and, so far, absence in the fourth transmembrane domain and in the carboxy-terminal region.

[Hemodynamic profile and serum cytokines in crush syndrome. Analogy with severe burns]. / Profil hémodynamique et cytokines sériques au cours d'un crush syndrome. Analogie avec les brûlures graves.

A 71-year-old woman remained under the rubble of her house for 4 hours after an accidental gas explosion. She suffered from a crush syndrome associating fractures, minor skin burns (< 10% body surface area), inhalation lung injury and moderate hypothermia (34 degrees C). In addition to local signs of compression of the lower limbs, the patient presented with hypovolemic shock and developed acute renal failure on day 3. We describe here the variations in hemodynamic and oxymetric parameters and cytokine response during the first post-injury week. A vasoplegic state resulting from low systemic vascular resistances with progressively increasing cardiac index, oxygen delivery and oxygen consumption closely followed the brief hypovolemic shock. Tumor necrosis factor-alpha remained below normal levels while interleukin-6 increased markedly with a major peak on day 2, in parallel with the drop in systemic vascular resistances. Interleukin-6 is a mediator of impairment in cell membrane function and a vasoconstriction inhibitor. Isolated increased interleukin-6 has been previously reported in severely burned patients suggesting a pathophysiological and hemodynamic similarity between crush syndrome and burn injury.

[Severe burnt patients: hemodynamic state, oxygen transport and consumption, plasma cytokines]. / Brûlés graves: état hémodynamique, transport et consommation d'oxygène, cytokines plasmatiques.

OBJECTIVE: To assess the haemodynamic and oxymetric variations measured by a pulmonary artery catheter and to correlate them with the variations of the circulating cytokines during the initial intensive care phase of severely burned patients. STUDY DESIGN: Prospective study covering an 18-month period. PATIENTS: Thirteen successive patients, aged over 12 years, without significant medical history, with a thermal burn affecting more than 50 percent of their total body surface area and admitted to our centre during the first six postburn hours. METHODS: The haemodynamic and oxymetric profile was investigated by inserting a blood flow-directed balloon-tipped pulmonary artery fiberoptical catheter. All patients were treated according to the protocol previously used in our centre. Blood samples were drawn on admission, every 12 hours post-injury until the 2nd day, then on the 3rd and 5th days. Cytokines were analyzed by Elisa method. Haemodynamic and oxymetric measurements were achieved simultaneously with the biological samples during the first 5 postburn days. The analysis of variance (ANOVA) with the Duncan test was utilized for multiple comparisons between continuous variables. RESULTS: (mean +/- SEM): The patients were 32 +/- 3 years-old and had a burn surface of 72 +/- 4%. After a short hypovolemic shock period lasting a 12 hours, a hyperdynamic shock occured which increased until the 5th day, with an increased cardiac index (6.9 +/- 0.4 at h120 vs 2.9 +/- 0.3 L.min-1.m-2 at h6, P < 0.05), increased oxygen transport and consumption (respectively 880 +/- 77 at h72 vs 543 +/- 58 mL.min-1 at h12, P < 0.05 and, 203 +/- 15 at h72 vs 129 +/- 25 mL.min-1 at h6, P < 0.05) and markedly decreased systemic vascular resistances (1,002 +/- 118 at h36 vs 2,330 +/- 328 dyn.s.cm-5.m2 at h6, P < 0.05). Circulating cytokines were not clearly modified except for interleukine-6 which reached early striking peaks (16,858 +/- 10,330 at h24 and 15,406 +/- 6,509 pg.mL-1 at h36) simultaneously with the decrease in systemic vascular resistances. CONCLUSIONS: During the first post-injury week, critically burned patients develop a specific hyperdynamic circulatory status during which interleukine-6 could be a mainfactor decreasing systemic arterial resistances.

[Evaluation of the cytotoxicity of antiseptics used in current practice on cultures of fibroblasts and keratinocytes]. / Evaluation de la cytotoxicité des antiseptiques utilisés en pratique courante sur des cultures de fibroblastes et de kératinocytes.

Infection is the greatest problem in burn patients and topical antiseptics must be chosen with great care especially when cultured skin is grafted. We examined the cytotoxicity of 6 antiseptics commonly used on cultured human fibroblasts and keratinocytes. Cultured cells were exposed for 15 min to Hibitane (chlorhexidine), Biseptine (chlorhexidine + benzalkonium chloride + benzylic alcool), dermic Betadine (polvidone iodine + nonoxinol), scrub Betadine (polyvidone iodine + quaternary ammonium) and gynecologic Betadine (polyvidone iodine). The cell viability was determined using the MTT test. At therapeutic concentration all the antiseptics were cytotoxic for fibroblasts and keratinocytes. The data suggest that the antiseptics must be used in function of the time of the grafting of the cultured epithelium.